Upgrading from 9.2 to 9.3 causes performance degradation

Hi,

Recently, I've been trough a datacenter migration, and in this operation I'd also upgraded my PostgreSQL version from 9.2 to 9.3. My new hardware is slightly better than the old one, but the PostgreSQL performance has shown degradation in the whole system.

Trying to figure out what could be happening, I'd installed instances of both versions on both servers, and double checked all the configuration parameters on them. The 9.2 version results make sense, there's a minor upgrade in the performance on the new server, but 9.3 number are worst than 9.2 on both servers, and surprisingly, worst in the newest than in the old one. After some research, I tried to disable transparent hugepages on the new one, but it made no effect. I used and specific query to benchmark, but as I said before, the whole system is slower.

Below is my data, and I really hope we can find what is happening, or I'll have to downgrade to 9.2 and wait for 9.4 release.

Old Server:
Ubuntu 10.04.4 LTS
2.6.32-45-generic

New Server:
Debian GNU/Linux 7.3 (wheezy)
3.2.0-4-amd64

Query Execution Times (average time of three executions, in seconds)

+--------+-------+-------+
| Server | 9.2 | 9.3 |
+--------+-------+-------+
| Old | 129 | 216 |
+--------+-------+-------+
| New | 118 | 275 |
+--------+-------+-------+

Thanks,

--
Álvaro Nunes Melo Atua Sistemas de Informação
alvaro(at)atua(dot)com(dot)br http://www.atua.com.br
(54) 9976-0106 (54) 3045-4144